Use of Where and having clause
780459Jun 21 2010 — edited Jun 21 2010Hi all,
I always have a doubt about use of HAVING and WHERE clause,
suppose I have table T1 with only one column C1
CREATE TABLE T1
(C1 VARCHAR2(1) );
which having data by following INSERT scripts
INSERT INTO T1 VALUES('A');
INSERT INTO T1 VALUES('B');
INSERT INTO T1 VALUES('C');
INSERT INTO T1 VALUES('A');
INSERT INTO T1 VALUES('B');
INSERT INTO T1 VALUES('A');
Now I want result as follows
C1 ==== COUNT(C1)
==============
B ===== 2
A ===== 3
So out of query 1 and 2 which approach is right ?
1) SELECT C1,COUNT(C1) FROM T1
WHERE C1<>'C'
GROUP BY C1
ORDER BY C1 DESC;
2) SELECT C1,COUNT(C1) FROM T1
GROUP BY C1
HAVING C1<>'C'
ORDER BY C1 DESC;
Edited by: user13306874 on Jun 21, 2010 2:36 AM